The chief reason (and what has been our great misfortune) that we have not been able to discover the cause of electricity, seems to be the leaving that philosophy, which has been _revealed_ to us, and putting in its stead _theories_ of _our own invention_. For, if we had considered (from the _revealed_ account that is given us of the formation of light) the _method_ of its _first_ production, we should not be at such a loss to account for that light in electricity, as we hitherto seem to have been; for we are _there_ told, that the _heavens_, or airs, were created in a state of _darkness_, or inactivity; and that the first thing God did, was to cause a _motion_, or _wind_ amongst the airs; which _motion_ was to _continue_, and _encrease_, till it produced _light_; and, after this _light_ was produced, God called it _Day_, or as it is expressed in the original, _tumultuousness_; it being produced from the impetuous or violent motion of the airs: and the _darkness_ he called _night_, or, as it is likewise expressed, the time when this _languishes_ or _decays_; for the _congealing_ or _thickning_ of the air, by which _darkness_ is produced, is in proportion as the _force_ of the _light_ abates. By all which, I think, we may be assured, that the _light_, and all the _phænomena_ produced in electricity, are caused by a violent _friction_ or _grinding_ of the grains of air between the glass globe and the hand. To illustrate and prove, that this is the method by which the electrical _light_ is produced, I shall bring some experiments, from Mr. _Hauksbee_, which, I imagine, will make it indisputable. In his first and second experiments, he shews us, that by dropping mercury on a glass in an exhausted receiver, the _action_ of the mercury on that subtil fluid gives the mercury the appearance of fire; but observes, that in all these experiments on mercury, no _light_ is to be obtained without _motion_, and that the same motion which produced this light in _vacuo_, did not produce it, when given to mercurial globules in _open air_. This experiment shews us, that there was a larger quantity of _light_ in the exhausted receiver than when it was filled with common air; nay farther, that the _subtil fluid_ contained in the exhausted receiver, was _light_; but, for want of _motion_, was not perceptible by our senses; but by so small a motion as that of the descending mercury, it was pushed forward in the same manner, as _light_ from a candle, or other luminous bodies. We also find, that the same experiments performed in an _unexhausted_ receiver, would not produce the _phænomenon_ of _light_; which one might easily suppose to be the case. For in the _exhausted_ receiver, any the least _motion_, that is sufficient to _push_ this subtil fluid (_light_) from one place to another must give us the perception of _light_; but in the _unexhausted_ receiver the _motion_ or _friction_ must be great enough,